Research

We study electron loss from specially synthesized organic amines that results in a molecular change in shape, color, electrical, magnetic, and chemical reactivity. An understanding of how electron content of a molecular influences it molecular properties informs our design and synthesis of new types of electroactive organic structures such as organic magnets, semi-conductors, charge-storage or charge-transport molecules, and organic mechanical systems that change shape with electrical stimulation.

High-Spin Poly Radical Cations - Appropriately structured amine radical cations have a chemically stable unpaired electron spin. Polyamines for which the amino radical cation spins are ferromagnetically coupled can be prepared to give a unique class of stable high-spin organic poly radical cations. The spin/magnetic content of these materials can be correlated with the redox state and thus switched reversibly by application of an external electrical potential.

Redox-Gradient Dendrimers and Charge Storage Molecules - We have prepared and studied a new class of electroactive dendrimers we call redox-gradient dendrimers, RGDs. These novel electronic structures have a globular shape and a core amino function of low oxidation potential surrounded external amino functions of higher oxidation potential to create a radical redox gradient within the nanometer size dendrimer space. RGDs have unique directional electron transport and charge trapping properties that make them useful as charge funnels or charge collectors at interfaces or on surfaces.

New Photo-Electrochromic Systems - By combining redox triggering of thermal reactions with photoisomerization chemistry, we have prepared some new types of photo-electro-responsive materials which undergo shape and color change in one direction under the influence of light and in the opposite direction under the influence of a electrical potential.

Electron Donor-Acceptor (DA) Bonding for Cocrystal Engineering- Exploration of intermolecular attraction between electron rich functions (donors, D )and electron poor functions (acceptors, A) via electrostatic and FMO overlap cohesion has led to a new set of DA bonds which form the basis for the growth and x-ray diffraction structure analysis of a set of DA cocrystals whose packing is strongly influenced by the intermolecular DA bonding. Novel and structurally exotic cocrystal structures can result and some predictive knowledge of cocrystal construction is possible based on observed DA bonding interactions as imaged by x-ray diffraction studies in a series of related cocrystals.